Ignition burner for pulverized-fuel-burning furnace



May 29, 1956 R. c. FARNHAM IGNITION BURNER FOR PULVERIZEDFUEL-BURNINGFURNACE Filed Aug. 25, 1952 3 Sheets-Sheet l mm mm W m mm Om mm mm May29, 1956 c. FARNHAM IGNITION BURNER FOR PULVERIZED-FUEL-BURNING FURNACE3 Sheets-Sheet 2 Filed Aug. 25, 1952 G m Z UWV May 29, 1956 R. c.FARNHAM 2,747,655

IGNITION BURNER FOR PULVERIZED-FUEL-BURNING FURNACE Filed Aug. 25, 19523 Sheets-Sheet 3 United States Patent Q l IGNITION BURNER FORPULVERIZED-FUEL- BURNING FURNACE Rex Couvelas Farnham, Woodley, Reading,England Application August 25, 1952, Serial No. 306,147

Claims priority, application Great Britain August 27, 1951 9 Claims.(Cl. 158-1) The invention relates to burners whether for use as mainburners or ignition burners, and is particularly applicable to ignitionburners for pressure raising and pulverised fuel furnaces.

It is one of the main problems in furnaces of this kind using fuelignition burners to safeguard the burner and the burner ignition meansfrom disintegration, due to the intense heat evolved.

In an effort to solve this problem it has previously been proposed tomount the burner and ignition means so as to be horizontally slidable inthe wall of the furnaces, whereby it is readily adapted to be withdrawnafter ignition has taken place. Such constructions have not provedsatisfactory in practice. A further disadvantage is that the oil may,due for example to non-ignition of the igniter, flow into the furnacewithout being ignited.

The invention has among its objects to avoid the disadvantages abovereferred to, and to provide a burner and ignition means which are somounted as to preclude the possibility of their being damaged by theintense heat evolved when the furnace is ignited.

The invention has further among its objects to provide an ignitionburner and associated parts which are of simple and robust construction,and efficient in operation.

According to the invention, the burner which in the position of useextends horizontally through an opening in the wall of the furnace ispivotally mounted so as to be adapted to swing outwardly, advantageouslyinto a position beyond the vertical plane of the outer surface of thefurnace wall, after ignition is completed.

The burner may be adapted to swing in a vertical plane or in ahorizontal plane or in any plane intermediate these two planes.

According to the invention furthermore, means are provided operating inconjunction with the burner, which are effective to seal the opening orport in the wall of the furnace in which the burner is mounted bothwhile the burner is in use and after withdrawal of the burner afterignition is effected. Such means may take the form of plates extendingfor example, mutually at right angles from a jointing position or at aninclination to the burner axis or at different radii to the burner axis,one of the plates extending horizontally beneath and parallel to theburner in the position of use and extending short of the burner tip atthe forward end to avoid disintegration by the heat of the furnace andserving also as a support for the burner, and the other (the longer)plate forming a closure for the substantially rectangular opening in thefurnace wall when the burner is in operation.

The ends of the two closure plates may be provided with arcuate guidemembers extending from the forward edge of the burner to the free end ofthe longer plate forming the closure to the port in the position of useof the burner, and serving as a cam in the pivotal with-' drawal of theburner after ignition has been completed, to bear against a springpressed member pivoted at the upper edge of the port or opening inthewall ofthe furnace which member is adapted to swing downwardly in thecompletely withdrawn position of the burner to complete the closure incooperation with the shorter of the closure plates secured to andextending beneath the burner, and overlapping the edge of the shorterclosure member to ensure an effective seal.

The burner operating means may comprise pistons movable in cylinderswhich are pivotally mounted at one end of a stationary base, the freeend of the piston rod being pivotally connected to the rear end of theburner. The piston may be operated hydraulically or by air pressure andmay be controlled electrically, by hand or automatically to move theburners into and out of the operative and inoperative positions.

According to the invention furthermore, the ignition means for theburner, advantageously electrically operated and extending adjacent andparallel to the burner, is mounted on the pivotal spindle of the burnerand is adapted to be moved into and out of the operative position by apiston moving in a cylinder with, and in the manner of, the burner.

According to the invention furthermore, the igniting: means may beprovided with sealing means in the form. of closure plates positioned toextend mutually at right: angles of the same kind as, and operating inthe same way, as the burner.

According to the invention moreover, a photoelectric: cell or theequivalent may be mounted between the guide rails connecting the ends ofthe closure plates and directed in such manner at an angle to thedirection of flow of the burner flame and out of the range of influenceof the pulverised fuel flame, as to be adapted automatically to cut-offthe supply of oil to the burner if the ignition means for any reasonforexample, a short circuit proves inoperative.

According to the invention furthermore, an automatically operatedpurging device or blower may be mounted on the inner lower peripheralsurface of the port or opening in the furnace wall, which is broughtinto operation as the burner swings into its operative position of use,and serves to purge or clear the lower ledge of the port or opening offuel, dust or other solid matter which may have deposited thereon, andwhich might operate to block or prevent the downward movement of theburner into the operative position.

According to the invention furthermore, automatically operated blowermeans and/or wiping means may be provided mounted in a convenientposition to ensure that the transparent covering of the photo-electriccell is clear of dirt or dust and/or oil and thus retains its accuracyin its control of the fuel how to the burner in the event of damage tothe igniter.

According to the invention furthermore, the burner may be provided witha flexible air connection or may be provided with a metal-to-metal jointwith packing interposed.

The invention is diagrammatically illustrated by way of example in theaccompanying drawings in which:

Figure 1 is a side elevation, partly in section,

Figure 2 is a corresponding front elevation, and,

Figure 3 is a side elevation of a modified construction.

The furnace to which the burners according to the invention may beapplied is a furnace of rectangular section burning a pulverised fueland having two or more fuel nozzles disposed, for example, at diagonallyopposite positions at the corners of the furnace, and extendinghorizontally at a convenient height in the furnace in what is known asthe ignition zone. Advantageously at midpositions between the pulverisedfuel burners are mounted oil fuel ignition burners formed as cylindricalmembers and adapted in the position of use to project horizontallyPatented May 29, .195

into the furnace, advantageously in the plane of the pulverised fuelnozzles.

Referring to the drawings, the oil is fed through an atomising nozzle 1of known type which is mounted centrally in a surrounding cylinder 2through which air is passed under pressure of, for example, 2-15 incheswater gauge. Means 3, comprising radial vanes, set at a determined anglein the mouth of the annulus impart a swirling motion to the air in itspassage out of the nozzle. Mounted above the cylinder 2 is a casing 4carrying an igniter 5 provided with an igniter element 6.

The oil pipe, the air feed pipe and the igniter element are mounted as asingle unit which is mounted on a supporting bracket 9 in bearings 10 ona transverse rotatable shaft 11. This the burner unit is adapted to bepivoted from the operative position shown in Figure l, to an inoperativeposition in which it is disposed vertically and completely outside thefurnace wall 12. Air is supplied through a fixed duct to a horizontalinlet 1.6 which is rotatable on a horizontally extending portion 17 ofthe fixed vertical duct 15 a seal 18 being provided between the fixedand rotatable parts.

The supply of air to operate the drive cylinder is electricallycontrolled from a control panel, located at any convenient position. Thesupply of oil is under the control of the two valves 27 and 28 which aremechanically operated by the movements of the burner into and out of theoperative positions.

The movement of the burner is effected through a drive cylinder 19pivotally connected at one end at 20 to the furnace wall and at theother end at 21 to a bracket 22 secured on the cylinder 2. Operation ofthe drive is through an electric relay and limit switch 23.

The horizontal movement of the igniter element 6 which is substantiallysimultaneous with the movement of the operation of an electric relay,withdrawn after a determined period, not greater than a few seconds.

The supply of oil to the nozzle is through filter 25, pipe 26, controlvalves 27 and 28, the valve 28 operating as a secondary cut-off valve incase of failure of the valve 27. The piping 29 leading to the rear endof the t burner is flexible.

A sealing door or plate 31 is provided to extend transversely of theburner in the operative position of use, being formed of rectangularsection, so as completely to cover the opening in the furnace wall.

An electronic viewer 30 is mounted to project through the sealing door31 which obturates the opening in the furnace wall when the burner is inthe operative position. The viewer 30 operates to draw the burner intothe inoperative position in case of failure of ignition. The viewer isset to operate through an electric relay after a time lag of a fewseconds, such time lag being greater than the period for lighting andwithdrawal of the igniter.

A wiper device comprising linkage 32 is operated by stops 33 and 33aprovided on the igniter on the withdrawal and insertion of the igniterto cause a wiping movement across the face of the viewer 30 of anasbestos cloth 34.

A rod 35 is fixed at the rear 36 so that in the withdrawal movement ofthe igniter element it engages a catch 37 on a pivoted door 38 to closethe end of the igniter casing, to prevent damage by burning to theigniter element.

The movement of the burner into and out of the operative position isguided by means of top guide rails 39 and bottom guide rails 40. Top andbottom sealing plates 41, 42 provided on the undersurface respectivelywith fins 43, 44 bear respectively on the top and bottom guide rails, sothat when the burner is withdrawn, and the door or plate 31 no longerobturates the opening in the furnace wall, the sealing plate 41 pivotsinwardly to meet the plate 42 carried on the burner casing, the end ofthe plate 41 engaging in a catch 45 provided on the underface of theplate 4-2 thus sealing the opening in the wall of the furnace on thewithdrawal of the burner.

Air under pressure is bled off from the main duct to the burner casing 2to cool the igniter housing 4: the top guide rails 39 are also cooled,being made hollow for the purpose, and if desired air is also bled offto cool the outer surface of the plate or door 31.

The electrical part of the apparatus is of known type, and itsconstruction forms no part of the invention: it includes relays, atransformer mounted on a panel 46 at the side of the burner. Thetransformer is adapted to provide a voltage of about 10,000 volts forstriking the arc of the igniter element. A guard 47 completely coversthe front of the apparatus.

In operation, the pressure of a button energizes a relay, causesoperation of the drive cylinder 19 to pivot the burner on the bearing,so that it comes to lie in the horizontal position of use illustrated inFigure l. Simultaneously, the movement of the burner operates throughlinkage 27a, 23a associated with the valves 27, 28 to permit a flow ofoil under pressure. Simultaneously the electric relay operates to drivefans to create a flow of air under pressure. Substantiallysimultaneously the electric relays operate to effect a forward movementof the igniter element and a striking of the are to ignite the atomisedspray of oil. and air. The igniter element is withdrawn after a time lagsuflicient to enable the are to strike and the door 38 is then closed.

Viewing observation holes 48 are provided in the door 31 which alsoenables the furnace to be lit by hand should the igniter element fail tolight the burner.

A hand-operated switch 49 provides a master control for the oil, air andhigh tension electric supply, whereby the guard 47 cannot be withdrawnuntil the switch 49 is operated to cut-off the supply of oil, air andcurrent.

Means comprising a hand-operated screw 50, are provided to adjust thefixed position of the oil pipe in the surrounding cylinder 2.

In the modified construction illustrated in Figure 3, the burner ismounted on a bracket 51 extending at right angles thereto, the bracketbeing pivotally mounted on a supporting bracket 52 secured on the frontof the furnace wall. The construction follows essentially thatillustrated with reference to Figures 1 and 2.

Modified linkage means 53 are provided to close the sealing plates onthe withdrawal of the burner.

It will be understood that although the invention has been describedwith reference to an ignition burner, it is not limited in itsapplication thereto, but may be applied generally in any cases whereburners, whether main burners, auxiliary burners or ignition burners,can be used in furnaces, boilers and the like.

Iclaim:

1. In a pulverized fuel burning furnace including a furnace wall havingan opening therein, a burner arrangement comprising: a support adaptedto be mounted externally of said furnace wall and adjacent said opening,means for pivotally mounting the burner on said support whereby theburner may be pivotally moved to extend through said opening in theoperative position, closure means carried by said burner for closingsaid furnace opening when the burner is pivoted to inoperative positionand power means mounted between said furnace wall and said burner forwithdrawing said closure means by pivoting the burner from theinoperative position to the operative position.

2. A burner as set forth in claim 1 wherein said burner carries anelectronic viewer and electric relay means responsive to said viewer forpivoting the burner to the inoperative position on failure of the burnerto ignite.

3. A burner as forth in claim 2 wherein said electronic viewer includesa wiper to clean the face of said viewer and means for mechanicallyoperating said wiper.

4-. A burner as set forth in claim 1 wherein said cover plate includesair supply means for cooling said plate.

5. A burner set forth in claim 1 wherein said burner carries fuel andair supply means, a removable guard surrounding the rear of said burnerand locking means for said guard operable to shut off the supply of fueland air to said burner before said guard can be removed.

6. A burner as set forth in claim 1 wherein said burner carries fuel andair supply means, and means operable to shut off the supply of fuel andair to said burner when the burner is pivoted to the inoperativeposition.

7. A burner as set forth in claim 1 wherein said drive means comprisepistons operating in cylinders, said cylinders being pivotally connectedto said support and said pistons being pivotally connected to saidburner.

8. In a pulverized fuel burning furnace, including a furnace wall havingan opening therein, a burner arrangement comprising: a support adaptedto be mounted externally of said furnace wall and adjacent said opening,means for pivotally mounting the burner on said support whereby theburner may be pivotally moved to extend 'through said opening in theoperative position, power means mounted between said furnace wall andsaid burner for pivoting the burner to and from the operative position,a major closure carried by said burner, a sealing plate pivoted to saidfurnace wall, and means coordinating movement of said closure andsealing plate when said burner is pivoted from operative position toinoperative 6 position to cause interengagement of said closure and sealto seal said opening.

9. In a pulverized fuel burning furnace, including a furnace Wall havingan opening therein, a burner arrangement comprising: a support adaptedto be mounted externally of said furnace wall and adjacent said opening,means for pivotally mounting the burner on said support whereby theburner may be pivotally moved to extend through said opening in theoperative position, first and second closure means mounted on saidburner for movement with said burner, said first closure means closingsaid opening when said burner is pivoted from inoperative position tooperative position, and said second closure means closing said openingwhen said burner is pivoted from operative position to inoperativeposition, and means mounted between said furnace wall and said burnerfor pivoting said burner to operative and inoperative positions.

References Cited in the file of this patent UNITED STATES PATENTS916,110 Creighton Mar. 23, 1909 1,001,863 Kirkwood Aug. 29, 19111,315,155 Pudney Sept. 2, 1919 1,371,490 Keller Mar. 15, 1921 1,719,608Holden et al July 2, 1919 1,733,647 Coghlan Oct. 29, 1929 1,876,509Stevens Sept. 2, 1932 2,361,117 Millett Oct. 24, 1944 FOREIGN PATENTS408,031 Great Britain Apr. 5, 1934

